Hydraulic jack for shoe machines



Feb. 13, 1951 F. R. THRESH HYDRAULIC JACK FOR SHOE. MACHINES 4 Sheets-Sheet 1 Filed June 24, 1948 m m w I Frank R. T/TreS/Z Feb. 13, 1951 F. R. THRESH HYDRAULIC JACK FOR SHOE MACHINES 4 Sheets-Sheet 2 Filed June 24, 1948 fnvenfor Finn/c R. 772 rash Feb. 13, 1951 F. R. THRESH HYDRAULIC JACK FOR SHOE MACHINES Filed June 24, 1948 4 Sheets-Sheet 3 Inventor Frank R. Thrash Feb. 13; 1951 F. R. THRESH 2,541,132

HYDRAULIC JACK FOR SHOE MACHINES Filed June 24, 1948 4 Sheets-Sheet 4 lnvenfor Frank E. Thrash Patented Feb. 13, 1951 UN [TED STATES PATENT OF F] C HYDRAULIC .JACKE'FOR SHOE MACH-IN ES Frank R. Thresh, "Beverly, Mass, assignor to United Shoe Machinery Corporation, Fleming- 'ton, N. J a corporation of New Jersey Application-11121112 24, 1948, Serial N 0. 34,903

This invention relates to shoe machines having fluid pressure operated jacks adapted to support shoes thereon and to locate such shoes in operative position with relation to the instrumentalities of the machine which are to operate upon the shoes. By Way of example, the invention is illustrated as embodied in a fastening inserting machine of the type disclosed in United States Letters Patent 1,849,253, issued March 15, 1932, on an application :filed in the name of Fred N. LaChapelle, it being understood that the invention is limited neither in scope nor in utility to embodiment in a machine of that type but that it may be used to equally good advantage in any machine in which the work is supported on a jack and presented in operative relation to the machine by the jack.

It is the general purpose of the invention to improve upon and facilitate the operation of the jack and more specifically to provide improved fluid pressure operated jack mechanism by means of which the jack will be moved into its operative position by a preliminary pressure which should be suflicient to clamp the work against the customary work abutment but should at the same time still permit adjustments of the work with relation to the work abutment. Increased fluid pressure thereafter will establish the final operative position of the work and at the same time initiate the power operation of the machine.

To this end and in accordance with an important feature of the mvention, the illustrated fastenine; inserting machine is provided with fluidpressure actuated jack-operating mechanism including a fluid pressure circuit with which are connected a. low pressure regulator and a high pressure regulator, an operator-controlled valve adapted to. connect the circuit with a jackelevat ing ram, additional means being associated with the valve for cutting off the low pressure regulater from the circuit after the elevation of the jack, thereby increasing the pressure of the fluid in the circuit and thus increasing the pressure of the jacked work against the work abutment.

In accordance with another feature of the invention, novel fluid-pressure operated clutch tripping mechanism is provided, which mechanism. is. connectable to the, above-mentioned fluid pressure circuit. The arrangement is such. that that mechanism is maintained in its inoperative l position until the pressure of the fluid in the circhit increases to a predetermined value, whereupon, the mechanism is. rendered operative to trip the clutch and to initiate the power operation of mlna ih fi 25 Claims. (Cl. 1- 4I) These and other features of the invention will now be described in detail in connection with the accompanyin drawings and will be pointed out in the appended claims.

In the drawings, I

Fig. l is a view in right-hand side elevation of a fastening inserting machine in which the im vention isembodied; v

Fig. -2 is a'sectionalong the line II-II of'Fig.

Fig. 3 is a plan view of a valve mechanism associated with the jack-elevating mechanism;

Fig. 4 is a section along the line I l-JV 0! Fig. 3,;

Fig. 5 is a section along the line V- -VofFig. 3;

Fig. dis a detail view of part of a treadle con' trolled valve-operating mechanism;

Fig. 7 is a schematic illustration of the aura pressure jack and clutch-operatin mechanism; and

Fig. 8 is a side elevation, partly in section, of another valve mechanism associated with the jack-elevating mechanism. 1

As already stated, the invention is illustrated as embodied in a fastening inserting machine of the type disclosed in the above-identified patent.

The machine disclosed in that patent serves the purpose of inserting fastenings around the heel end of a shoe bottom. In the particular instance, the illustrated machine is adapted to insert fiber fastenings which are severed from a strand oi fiber-fastening material and then are successively driven into the work. The work. is supe ported on a jack and is intermittently fed past the operating instrumentaliti'es of the machine. These instrumentalities include an a'wl (not shown) which is caused to pierce the work and; while remaining in work-piercing position; to feed the work laterally of the machine a prede termined distance. Thereafter the awl is with drawn from the work, the arrangement being such thatthe hole made in the work by the awl is now located in register with a fastening inserting driver (not shown). In the meantime a fac tening or peg has been severed from the strand of fastening material and has been transferred into the line of drive beneath the driver in r'ead i mess to be inserted by the driver into the hole made in the work by the awl. Work is supported on a jack and the jack is mov able to locate the work in operative position in which it is maintained by the clamping pressure of the jack. in readiness for the awl to pierce the work. However, prior to the work-feeding motion of the awl-;the: clamping pressure or the jack 18 As stated, th'

marily to improve upon the jack-operating mechanism, including the mechanism for causing the periodical relief of the clamping pressure of the jack during feed movements of the awl, and the clutch-tripping mechanism which, for its operation, depends upon the jack-operating mechanism.

The machine illustrated in Fig. 1 of the drawings has a frame base in carrying a column [2 on which is supported themachine head It housing the operating instrumentalities of the machine and. their actuating mechanisms. The shoe-supporting jack is indicated at It and is of well-known construction. As usual, the jack has a last pin l 8 which is adapted to enter the thimble hole of a last on which the shoe to be processed is mounted. A shoe gage 26 of well-known construction is adjustably mounted in the head 64 and determines the distance of the driven fastenings from the edge of the shoe bottom, morespecifically, the edge of the heel end portion of the outsole. Moreover, there is secured to the head I4 21. Work abutment 22, also well-known in the art, against which the shoe is adapted to be clamped by the jack upon elevation of the latter. Rotatably mounted in the head 14 is a cam shaft 24 which carries and is driven by a clutch having the usual driven and driving members 26, 23, the driving member 28 being a pulley. The pulley 2B is driven by a belt 3!! connecting it to a pulley directly driven by an electric motor 32.

-' The illustrated machine is provided with clutch-tripping mechanism for initiating and terminating the rotation of the clutch shaft or cam shaft 24 and, with certain modifications to be presently described, this clutch-tripping mechanism corresponds to the clutch-tripping mechanism disclosed in the above-identified LaChapelle patent. There is mounted on the cam shaft 24 a clutch-controlling spring 34 (Fig. 1) and the'hub of the driven clutch member 26 carries a loose ring 35 engaged by a yoke 38 which serves the purpose of throwing out the clutch against the force of the spring 34, the latter tending to throw in the clutch. The yoke 38 is mounted to rock about a fixed stud 4il'and its lower end is connected by a toggle 42 to a lever 44 which is pivotally securedat 46 to the head l4.. The lever 44 carries at its upper end a cam roll 48 which is in engagement with one end face of a cam block 58 secured on the shaft 24. This end face has a cam portion or rise (not shown) which during each revoultion of the cam shaft 24 moves once past the roll 48 and swings the lever 44 in a clockwise direction (as viewed in Fig. 1). The center joint of the toggle 42 is connected by a link 52 to an arm 54 on a'shaft56 rotatable in the head 14. Another arm 58 on theshaft 56 is pivotally secured to a vertical clutch-controlling rod 6|]. in clockwise direction (Fig. 1) is limited by engagement of a stop 62 on the arm with the head -l4. The rod is guided by a bracket 64 through which the rod extends. A spring 66 on the rod 60 is confined between the bracket 64 and a fixed collar 58 on'the rod and-tends to depress the rod Swinging movement of the arm 58 4 60 and to swing the arm 54 in a clockwise direction (as viewed in Fig. 1) to maintain the toggle 42 straight.

The cam portion on the end face of the cam block 50 is so located thereon that the lever 44 is swung in a clockwise direction (as viewed in Fig. 1) toward the end of a machine cycle. If the toggle 42 is straight, this results in rotation of the yoke 38 in a counterclockwise direction (as viewed in Fig. 1) thereby throwing out the clutch against the pressure of the sprin 34 and stopping the machine. However, if the toggle 42 is broken, this clockwise swinging movement of the lever 44 is merely an idle motion and the machine operation continues. Thus in the stopping position of the machine the lever 44 is swung out toward the right of Fig. 1, the toggle 42 is straight, and the clutch is disengaged. To initiate a new machine operation the toggle 42 must be broken and this is efiected by an upward movement of the clutchcontrolling rod 60 against the pressure of its spring 66. As a result of breaking the toggle 42 the spring 34 now is free to trip the clutch, that is to reestablish driving engagement between the two clutch members 26, 28 and initiate the machine operation which will continue indefinitely as long as the toggle'42 is held broken. However, as soon as the rod 60 is permitted to be lowered by the spring 65, the toggle 42' will be straightened again so that the next swinging movement of the lever 44 toward the right of Fig. 1 will again cause the clutch to become disengaged.

As in machines of this type the jack [6 is movable in the heightwise direction of the machine so as to locate the shoe supported thereon in operativeclamping position against the abutment 22. The specific construction of the jack is, so far as the present invention is concerned, immaterial and the jack may be of any suitable shape. The jack I6 is supported on a vertically movable rod 10 (Fig.1) slidably guided in the machine frame. The lower end of the rod 10 is pivotally secured by means of a pin 72 to a 3 two-armed lever 14. The lever 14 is adapted to rock about a horizontal stud i6 which, as will be described, is arranged for vertical movement in the machine. The lower end of the rod 10 is provided with an abutment 18 which is adapted to cooperate with a stop 30. The stop is secured to the machine frame and is ve'rtically adjustable with relation thereto. The stop determines the lowermost position of the rod 19 and, accordingly, of the jack IS. The

- right-hand end (Fig. 1) of the lever 14 is pivotally connected by a pin 82 to a link 84 which in turn is pivotally secured to a bell crank lever 86. The bell crank lever 86 is mounted for swinging movement on a fixed pin 88 and its horizontal arm is pivotally connected to a link member 90 which is secured to the lower end of a cam-controlled rod 92. the link 84 and the vertical arm of the bell crank lever 86 constitute a toggle which is made or broken by swinging movement of the bell crank lever 86 about its pin 88 under the control of the link 90 and rod 92. The, upper end of the rod 92 is pivotally secured to a bell crank lever 94 which is mounted to swing about a fixed pin. and the vertical arm of which carries a cam' chine cycle. The configuration of the cam As will be noted,

cause swinging movement of the lever 14 about.

the pin 82 in a clockwise direction (as viewed in Fig. 1) to elevate the. rod I and jack I6. This elevation of the jack, as already mentioned, causes the shoe supported thereon to be moved into. operative position with relation to the op.-

erating instrumentalities of the machine and to be maintained in that position by being clamped against the abutment 2.2.

It has been mentioned that. the work is inter, mittently fed, there being one feed movement during each cycle of operations. In order to permit the work to be fed, it is of course, neces. sary temporarily to release its clamping engage, ment with the abutment 22 by a short downt ward movement or dip of the jack I6. This dip is effected and controlled by the above-described bell crank lever at to which swinging movements are imparted by the cam groove 98. More specifically, immediately prior to the beginning of av work-feeding movement, the bell crank lever 94 is swung in a clockwise direction (as viewed in Fig. 1) to depress the rod 92 and break the toggle 84, 85. Considering for the moment the stud T6 to be vertically immovable, it will be seen that the breaking of the toggle results in a rotation of the lever I4 in a counterclockwise direction (as viewed in Fig. 1) about the stud I6. This rotation in turn causes the jack It to move downward sufficiently to relieve the clamping pressure of the shoe against the abutment 22. After the completion of the workfeeding movement, the cam groove 98 causes the bell crank lever 94 to be swung back, that is to be swung in a counterclockwise direction (as viewed in Fig. 1), thereby elevating the rod 92 and again straightening the toggle 84, 8B. This causes rotation of the lever I4 in a clockwise direction about the stud I6 and a reelevation of the jack It as a result of which the shoe is again clamped against the abutment 22'.

The illustrated machine is provided with fiuidpressure actuated mechanism for elevating the jack I6 at the beginning of an operation on the shoe and for initiating the power operation of the machine by the actuation of the abovedescribed clutch-tripping mechanism. The are rangement is such that the jack is elevated with a low pressure sufiicient to clamp the shoe against the abutment 22 but insufiicient to resist slight adjustments of the shoe with relation to the. abutment 22. After locating the shoe in its proper operative position the fluid pressure is increased to produce a final shoe-clamping pressure and simultaneously to Operate the clutchtripping mechanism. To this end the abovementioned stud i is mounted in ears I 08 (Figs. 1 and 2) provided on the upper end of a piston rod H32 which with its piston I04 constitutes a ram that is vertically movable in a closed cylinder I05 bolted to the machine base ID. The upper end 7 of the cylinder 166 is closed by a cap Hi8 having a connected by a conduit I I4to a gear pump Hi5 driven-bye belt connecting it tothe pulleyon the rotor shaft of the motor 32. The pressure side of the gear pump is indicated at I It.

The pressure side IIB. of the pump. H6 is in direct communication with a conduit or passage I20 (Figs. 4 and 7) which is provided in a valve block I24. The valve block I24 is bolted to the inside of one of the walls of the sump casing H2. In constant communication with the pas,- sage ,I2il is a high pressure regulator I25 of well-.- known construction. The high pressure rogue later I26 is mounted in a vertical bore I28 (Fig. 5) provided in the valve block I24. The lower end portion of the bore I28 which is closed con. tains a sleeve i352 having diametrically opposite ports 532 so that the pressure fluid may pass from the left-hand portion of the passage I20 (as viewed in Fig. i) to the right-hand portion of that passage. Slidably mounted in the sleeve I39 is a valve plunger ltd carrying on its upper end a thimble I35 which supports a spring I 38 housed in cup-shaped plunger I40. The plunger I4!) is vertically movabl in the enlarged upper portion Hi2 of the bore 428 and abuts: with its upper end a set screw Hit. The set screw passes through a lid Idii which closes the upper end of the bore I 28 and which is secured by screws I48 to the top face of the valve block I24. The screw ted is held in adiusted position by a. locking nut I50. Adjustment of the screw I44 accordingly results in adjustment of the pressure of the spring I36 and thus in adjustment of the pressure at which the regulator I26 will open to permit the pressure fiuid to spill over through the regulator. More specifically, when the presy sure in the passage I29 exceeds the pressure for which the regulator 52s is set, the valve plunger I34 will be raised so that its upper head opens the upper end of the sleeve I38, permitting the excess pressure fiuid to enter the enlarged upper portion Hi2 of the bore 128 and to flow from there through a conduit 552 back to the sump.

The pressure fiuid flows through the conduit I29 to a jack-operating valve I54 (Figs. 4, 5 and 7) also mounted in the valve block I24. The jack-operating valve I54 is arranged for sliding movement in a vertical bore I53 extending from the top to the bottom of the valve block I24. The passage I2il communicates with the bore I55,

as illustrated best in a of the drawings. The

valve Ifi i comprises a plunger or stem I58 having lower and upper valve heads I60 and I62. About midway between its upper and lower ends the bore I56 is provided with a port I54 which is in communication with a conduit I66 that leads to a low-pressure regulator or relief valve I68 (Figs, 2 and 7) also of conventional construction, but, as the name already indicates, set to maintain a considerably lower pressure than that main tained by the hi h-pressure regulator Ii26.- Any fluid which may escape through the low-pressure regulator 558 is conducted back to the sump through a conduit Ili! which connects the lowpressure regulator i8 with the sump casing H2 (see Fig. 7)

The above mentioned jack-operating valve I5 8 is, as will be described in detail, controlled by the operator, its normal or inoperative position being illustrated in Figs. 4, 5 and 7. The bore I56 in which the valve list is movable has near its fiuis'to flow-from the conduit 12o through'the. I

middleportion of the bore I56 out of the port I72 into the conduit I'M. Accordingly, with the pump I It in operation the pressure fluid is moved idly in a circuit which includes the sump, the conduit IN, the gear pump He, the conduit I20, the bore I55, the conduit I'M, and again the sump. The pressure of the fluid whichis thus delivered by the pump is determined and controlled by the low-pressure regulator I58 which, as described, is in communication through the conduit I66 with the bore I56. The valve heads I60, I82 prevent escape of the pressure fluid into and through the lower and upper portions of the bore I58.

The lower end of the bore I56 which in. the normal inoperative position of the valve I55 is cut off by the valve head I68 from the above defined circuit has aport lit with which communicates a conduit or passage I18 (Fig. The passage I18 in turn is provided with a port I80 with which communicates a conduit I82 (Figs. 1,2 and 7). The conduit I82 is in communication with the lower end of a cylinder I34. The cylinder I84 is mounted for limited rocking movement on a ,pin I86 carried by a bracket I88 secured to the column I2. Vertically movable in the cylinder I84 which is open at its upper end is a clutch-operating piston or ram I95 which is integral with the lower end of the abovedescribed rod 68, upward movement of which causes the tripping of the clutch 2B, 28. The upward movement of the piston Iilt and the rod 66 is resisted by the spring 65 (as already mentioned) and only when the fluid pressure becomes strong enough to overcome the resistance of the spring (56 will the piston I9!) be displaced upwardly in the cylinder I82, thus elevating the rodte and throwing in the clutch. The abovementioned passage H8 (Fig. 5) is in communication with a locking valve I22 located in the valve block 122, and serving to lock the. jack against downward movement, as will be described. Referring specifically to Fig. 5, it will be seen that the valve I92 is located in a bore I94 provided in the valve block I24, the lower end of the bore being closed by a plug I95. Mounted in the bore E94 is a sleeve I98. lvlovably mounted in the sleeve I98 is a valve plunger 2% having at its lower end a valve head 222 which cooperates with a valve seat formed at the lower extremity of the sleeve I983. The sleeve E93 has at its upper end a flange 264 extending over the top of the valve block E24 and secured thereto by a screw 206; To close the valve I 98 the following arrangement is made. The plunger 228 extends a certain distance above the upper end of the flange 204 of the sleeve I83 and is surrounded by a spring 208. The lower end of the spring 258 rests against a washer or plate on the flange 2% and the upper end of the spring abuts a collar 210 secured to the upper end of the plunger 295]. It will be noted that the spring 298 tends to elevate the plunger 20!) and, therefore, to close the valve I92. The valve I92 is opened by depression of the plunger 20!! against the pressure of the spring tion and operation of the time delay valve will be described later on. L FE-Kie i 3 Plm r '49P eedio e valve The conduit 2M leads to a time delay valve I 92, the upper end of the plunger 20!) is adapted to be engaged by an arm 2I8 (Figs. 1, 2, 7 and'il) secured on a shaft 220. The shaft 220 is rotatably mounted in a bracket 222 which is bolted to the sump casing II2. Another arm 224 is secured to the shaft 220 and is pivotally connected by a rod 226 to the above-described link 9E] which serves to operate the toggle 84, 86. Downward movement of the rod 92 and the link 92 under the control of the cam groove 98 thus not only breaks the toggle 84, 86 but closes the locking valve I92 in causing the arm 2I8 to swing up, thus permitting the spring 288 to elevate the valve plunger zen.

To enable the operator to move the jack-operating valve I54 so as to cause a movement of the jack into operative position and also t initiate the power operation of the machine, the following mechanism is provided. The upper valve head I62 extends above the valve block I24 and is pivotally connected at 22%) (Figs. 4 and 5) to a two-armed lever 230. The lever is mounted to swing about a horizontal pivot 232 (Figs. 4 and 6) which is carried by a bracket 234 secured to the sump casing H2. A link 236 (Fig. 6) connects the lever 230 with a collar 238 clamped on a rod 243. The lower portion of the rod is passed through a bore in a casting 242, the rod being held in fixed relation to the casting 242 by clamping collars 244 and 246. -Thus, rod 243 and casting 242 may move as a unit. The lower end of the casting 222 is pivotally secured to a two-armed treadle lever 248 (Fig. I) mounted to rock about a fixed horizontal pivot stud 25s. The outer or forward end of the treadle is engaged by a spring 252 which tends to pull the forward end of the treadle up against snubber or dash pot 254, the purpose of which is to dampen the upward movement of the forward end of the treadle to prevent that end of the treadle from rebounding and initiating another power operation of the machine. r

The above-described bracket I88 to which the cylinder E84 is pivotally secured has a downwardly extending portion 256 (Fig. 1) provided with a bore 258 open at its lower end. Received in the bore 258 is the upper end of the rod 246, the movements of which are thereby guided. The rod 246 carries a spring 265 which is confined between an upper collar 262 slidable on the rod 248 and a lower clamping collar 2% fixed on the rod 246. Accordingly, on elevation of the rod 246 the collar 252 is ultimately brought into engagement with the portion 255 of the bracket I88 with the result that the spring 2636 becomes compressed and offers resistance to the continued upward movement of the rod 249. The purpose of thisarrangement will be described in connection with the description of the machine operation.

The above-mentioned time delay valve 2 I 6 comprises a casing 255 (Fig. '7) with the intrior'of which is connected the already-mentioned conduit 2 i l. Before the conduit 2 It enters the easing it has a branch conduit 258 leading to a different portion of the casing, as will be described. The pressure fiuid entering the casing through the conduit 2 It encounters a ball valve 276 which is opened to permit the fluid to pass unimpededthrough the delay valv into the conduit H0. Provided in the casing 236 is a chamber 212 in which is movable a spring-biased hollow plunger 27 i. The chamber 2'52 is provided with an an 7 nular groove 276 which establishes direct comentering through conduit 2' can always flow unimpeded to the conduit it and the cylinder Hi6 to elevate the jack-operating piston I04 end face ofthe plunger 2% toovercome theflight resistance of its biasing spring. The result of this is a rapid displacement of theplunger 47 4 toward the left of Fig. 7 against the pressure of its spring so that the right-hand end of the plunger 2% is displaced sufiieientlytoward the left of Fig. 7 to establish commdniea-tion between the lower endof the conduit We and the righthand end portion of the chamber 212. condition obtains while the cylinder Hi5 is'underpr'essure, the" piston N34 is up and the jack in its elevated operative position. If new the passage We is cut :ofi from the source of pressure iiuid by'the elevation of thetreadleiii'and the r'ai'sihg of the valve- 554 into its normal inoperative positive" (shown-in Figs; 4 and 5) theflnid oont'ained the oylihder m6 and the Conduit PH) cannot irnrriediately escape hack to the passage l lB but is" hy-passed through the above rnentioned' some rnunication between the iower' end of thec'onduit HiJand the right-hand end' portion of'the chainber' 272" through. a'needle" valve 289 arranged in a passage which is in communication with the branch conduit 268 The lowering of the piston IE4 and the jack I5 is thus delayed until after thepressure" of the: fluiditrappedin the cylinder IGtfand conduit Ht has been reduced 'suflieiently through theieakage cffthe pressure 'fiuid" past the needle valve 280 to permit theplungerfllto be returned toward its rightmand' position by its spring. As soon as an annularrecess provided in the periphery of 'thep lunger" 2741s; in Communication with the .lower' endof the conduit l'ifltth excess pressure fluid inithecylinder I116 and conduit H o'is 'quickly exhaustedvia the annular re'cessZBTwhich iSIii'l'idiIECt communication with thecnnduit'ZM. Thepressure fiuidflowin'g back through theiconduits 268 and 214 andl th'e open locking valve I92 is drained outflthrou gh the passage I78 and the loweren dof the bore l'fi'tback into thesump; The sattingoftheneedIe valve 280 determines thetime dela'yin' the lowering ofthe jack;

Thepurposeof theprovision of the time delay valve Tlt'i'sto insure that on stopping the machine operation the last" fastening isseeurely driveninto the work. It'may occur that the operator in releasingthe treadle 248'toeutofFtlie passage I18 andj eonduit 82 from the source of pressure fluid will'inadvertentlydelay this action som what by not taking his foot off l the treadle duicklyienough with the'resultthatithe cam portion on the end face of'the cambl'ock will move past" the cam roll 48 and thus permit the initiation of another cycle of operations even though the valve l5.4has beenrais'ed to out off i the passage H8 and the conduit" I82" from the supply of pressure ,fiuid and to initiate theiexhaust' of excrss pressure 'fiuidfr'orn the passage I'EB' a-ndthe eonduit182; Accordingly, 'iidi'otiine delay valve were provided between 1 the passage liB and the jack-operating cylinder-i iifi the-ja'ck would descend immediately and" the' last faste'ningproduced asthe're sult of the additional eyele 0t rlonerati'on :above mentioned would: be incompletely driven into theishoeisince: the Platter would movement e the" cylinder tilt and ezhausted quickly without aetion on the part of the time delay J. 06k the jack I 6 against undesired further 1115mm movement at a erta in tiine during a ej-ycieof operations the following hydraulic locki-n mechanism has been provided. Mounted on the sninp' 'casi'ng H2 is a valve casing 284' (Figs. 1, f, 7' '8) which eonta'i' ns an oil reservoir" 286. The oil reservoir 236 in communication by meansof a port and passage 288 with a bore 290 a. 8)" whieh is vertically movable a valve s linger 292. The lower portion of the valve plunger 292 is-of reduceddiameter and carries at its lower extremity a valve head 294 which cooperates with a: valve seat formed by ashouldered portion ofthebore 299-. A spring EQ'ittends to J. aise the-plunger 292 and press the valve head fii l against-its seja't toclose the valve; The upper end of' the spring engages the valve head 2584 the lower end of the spring is seated in' m axi'a'l hore' provided a cap screw 292 w ich closes the lower end of theb'ore 290; The passage i'n c mmum'cau n with the bore above the valve head 2.94. "Belowthe valve head 2'94 the h re-res is in communication with a 'cbndnit i1iiiinvhich leads to theupper portion of the cylinder 1 Thereservoir 233" being filledwithpil an'd heingopentb'th'e atmosphere, it will b'e'u'ndersteodthat-with the valve zezop'en the down ward movement of the piston Hi4 sucks oil frorn the reservoir Z-B'G'thmugh theopen vaive'ziti and 'oo'ndiritttt ihto-the-upper'riortion ofthe'cylinde'r N36 above the piston F043 Reverseiy, upward movement of the piston 34 displacesoilfrjomthe upper portion ofthe cylinder H16 through the conduit 309 and open valve 292 back into the r'esei'voirwli Ho'weveh'it will a'1s0be understoo'd that iithe'valve 292* is closed nosuch oil can be dishlac'edfrom the upper' portion of the 'eylinder its; thus iooking the piston 104 against upward "rom -en thef-v'al've 2 92 against'the ressured: the; spring 296'; the followingm echanism is provideo;- The abeverhentioned shaft 22i1- to which is' 's'ecurfied thar'lil 2 18 operating the valve I92 also has" secured to it an arm m- (Fig. e); the free en'd of-which-is'-pivotallyconnected by aliiik 3'9'4'to-a tw0 arined lever 3%" adapted torock ahout a pivot piii MEE -carried in a brachettln "secured tothe valvenasing 2 842 The left-hand arm (as seen iii Fig: 8) of the lever 3- t' is mengager-n'ent with the-upper end ofth'ev'alve plunger 292 which projects beyond the valve'casing 284s It will ice-noted that' rotation of the" shaft 226', -as =above assented, to permit the c'io's-iiidf the valv'e' l 92 say its spring 2 e8 wil1 =rotate thelever BEES- in -a cloekwise direction as viewed in' Fi'g." 8) thus simultaneously permitting the spring 2 9'6 t'o ciosevmve 292 ccordingly; the piston we is sirnultaneouslydockd against downward and' upward movement by threSiieo'tiVwzzlvs i921 and 292':-

The machine 'operation is suh'stantially 'as' follows; After a'lasted-shoe has beenlplaeedupon the iast pin 1 a of'the ja'ck G and after th'e motor 32 'hasbeeh started, thereby:causing:the piin'ip M 5 ito operateaand' to circulate the pressure fliii'd idly in: the" abOVEdeSCF-ibbd circuit i :t 2} l H 4*, @H 5, M8" 295 lSEMBBMH; andoba'ok to the sump H2 xthe'io-perator stepsron :the :treadle '248 liand causes the upward movement of the casting 242 and rod 240 (Figs. 1 and 6) as a result of which the lever 230 is swung in a clockwise direction (as viewed in Fig. 7) to depress the valve I54. It is port I12, thus preventing further escape of the 1 pressure fluid back to the sump through pipe I14.

In stepping on the treadle 248 the operator depresses it only until he feels the resistance of the spring 260 at which time the port I16 leading to passage I18 has been fully opened so that the pressure fluid can enter through the then open locking valve I92, conduit 2I4, delay valve 2I6, and conduit I I into the jack-operating cylinder I06, thus causing the elevation of the piston I04 and, accordingly, the elevation of the jack I6 to clamp the shoe against the abutment 22.

The elevation of the jack is accomplished brief ly as follows. It has been mentioned that in the inoperative position of the machine the toggle 84, 86 is straight and is positively maintained in that position. With the toggle being held straight, the locking valves I92 and 292 are simultaneously held open as the result of the connection of the valve-operating arms 2I8 and 302 with the toggle-operating link 90. Elevation of the jack-operating piston I04 causes elevation of the stud 16 and swinging movement of the lever 14 in a clockwise direction (as viewed in Fig. 1)

about the pivot 82, thereby elevating the jack It as described. As already mentioned, this is efiected under low pressure since the bore I56 is still connected by the conduit I66 to the low-pressure regulator I68.

With the opening of the port I16 to the pres- ,sure fluid, by virtue of the head I60 now being below port I16, the port I80 (Fig. is also opened so that the pressure fluid also can flow through conduit I82 and act on the clutch-operating piston I90. However, the spring 66 which opposes the upward movement of the clutchoperating piston I90 under the action of the pressure fluid is sufficiently strong to prevent such upward movement after the conduit I82 has been opened to the pressure fluid so long as the pressure of the fluid in the conduit I20 and bore I56 is controlled by the low-pressure regulator I68.

The shoe having been clamped against the abutment 22 under the action of the low-pressure fluid against the jack-operating piston I04, it is still possible to make adjustments of the work with relation to the abutment 22 and edge gage 20.

After the final position of the work in the machine is deemed satisfactory the operator fully depresses the treadle 248, thereby causing further downward movement of the operating valve I54 with the result that the upper valve head I62 closes the port I64 and disconnects the conduit I66 from the bore I56. Since the lowpressure regulator I69 is now out oif from the supply of pressure fluid, the pressure of the fluid is now controlled only bythe high-pressure regulator I26 which, as previously described, is continuousl in communication with the passage I20. The result is an increase of the pressure of the fluid in the passage I20, the bore I56 and the conduits I18 and I82 so that the jack-operating piston I04 isnow maintained in its uppermost position under the full pressure of the fluid,

-12 thus causing the shoe to be clamped with full pressure against the abutment 22. Moreover, the increase of the pressure of the fluidin :the conduit I82 is suiflcient to overcome theresistance of the spring 66 to the upward movement of the clutch-operating piston I90. Thus the piston I is thrust upward to break the toggle 42 and permit the spring 34 to move the clutch member 26 into engagement with the clutch member 28. This initiates the power rotation of the cam shaft 24, and the operation of the instrumentalities of the machine which are controlled by the cam shaft 24. It will thus be noted also, that the power operation of the machine cannot be started, unless and until the jack is up in its operative position.

It has been mentioned that at the beginning of a machine cycle the awl is caused to pierce the work whereupon the awl is caused to move laterally of the machine tofeed the work. Prior to the work-feeding movement of the awl the cam groove 96 imparts a swinging movement to the bell crank lever 94 in a clockwise direction (as viewed in Fig. 1) as a result of which the rod 92 is depressed. The depression of the rod 92 results in three things, namely, the toggle 84, 86 is broken, the arm 224 is swung in a counterclockwise direction (as viewed in Fig. 1) to permit the closing of the locking valve I92 by the spring 206, and the arm 302 is swung in a counterclockwise direction (Fig. 8) to permit the closing of the locking valve 292by the spring 296.

The closing of the valve I92 results in locking the piston I04 against downward movement since the pressure fluid in the cylinder I06, the'conduits H0, 2M, and the delay valve 2I6 cannot escape back into the conduit I18. Thus the stud 16 becomes a fixed pivot for the lever 14. The breaking of the toggle 84, 66 results in a short rocking movement of the lever 14 in a counterclockwise direction (as viewed in Fig. 1) about the stud 16 and this in turn causes a brief downward movement or dip of the jack l6 suflicient to relieve the clamping pressure of the shoe against the abutment 22 to permit the shoe to be fed by the awl.

As just described, the brief downward movement or dip of the jack I6 during the work-feeding operation of the awl is caused by a breaking of the toggle 84, 86 which results in a rocking movement of the lever 14 in a counterclockwise direction (as viewed in Fig. 1). It has been observed, however, that since the breaking of the toggle 84, 86 is apt to occur much faster than the downward movement of the jack I6, the lever 14 is apt not to rock about the stud 16 as it should but to swing in a counterclockwise direction (as viewed in Fig. 1) about the pin 12. This would elevate the jack-operating piston 04 and possibly interfere with the proper feed motion of the work, were it not for the provision of the additional locking valve 292 (Figs. '1 and 8) which prevents such upward movement of the piston I04 at the time the jack I6 receives its brief downward movement or dip during the work feeding operation. 7

As previously explained, the valve 292 is operated simultaneously with the locking valve I 92 by connections to the same shaft 220, there being oil at opposite sides of the piston I 04 which at the feed interval becomes locked by the respective valves I92 and 292, thus effectively preventing the downward, as well as the upward, movement of the piston I04 and, accordingly, establ3 lishing the stud 16 as a truly fixed pivot for the lever 14 during the downward movement or dip of the jack;

After the completion of a work feeding movement the cam groove 9s causes a reverse swinging movement of the bell crank lever 94 in a counterclockwise direction (as viewed in Fig. l) to elevate the rod 92. The elevation of the rod 82 again opens the locking valves M2, 2% so that the full hydraulic pressure again can act on the jack-operating piston we to elevate the jack The elevation of the rod 92 also causes the toggle fi l, 36 to be straightened. The timing is such that the toggle is straightened before the the straightening of the toggle takes place while the stud is is still held fixed in the machine. Thus on straightening of the toggle lid, 85 the lever 74 is swung in a clockwise direction (as viewed in Fig. 1) about the Stud 56 to reelevate the jack and to restore the clamping pressure of the shoe against the abutment 22.

l The machine cycle will be repeated indefinitely as long as the treadle is maintained depressed. release of the treadle the valve its is again raised to its normal inoperative position in which thepressure fluid may circulate idly in the fluid pressure mechanism, the clutch-operating cylinder I8'4 and the jack-operating cylinder I65 becoming cut oii" from the supply of pressure fluid by the upward movement of the lower head lei} of the valve [5A. Excess fluid in the conduits Hi8 and l 82 spillso'ut through a drain passage, which aictually is the lower end of the bore 551?, back into the sump casing H2. The piston I04 is brought back to its initial lowermost position under the Weight of the parts supported by it and the clutch-operating piston I90 is lowered by the spring 66. Lowering of the piston I04 causes a lowering of the jack it into its inoperative position. Lowering of the clutch-operati-ng piston 89% causes the toggle 42' to become straightened and the clutch member 2$to be disengaged from the clutch member 28 by the portion on the end face or" the cam block 50 aeting on the camroll 48:, All machine parts having been returned into their initial positions, the machine is now ready for the initiaton of tliope'ration upon the next shoe to be processed, 5 Having thus described my invention, what I claim as new and desire to secure by Letters Patent'ofthellnited States is: H

1. Ina shoe machine, a movable shoe-sum porting jack adapted locate a shoe in opera ti v'e'position in the machine, fluid-pr sure mechanism for moving the jack, a flui' r ssure circliit' including a pressure generating source, a valve for establishing @cn'lmcaieauon between said mechanism said circuit, and selective means anished with the valve for causing incre e or the pressure of the iiuid in said circuit a. or the jack has the shoe'in operative position. 7 2. In a" shoe mac a movable shoe-sun poiting jack adapted to locate a shoe in operative'" position in the machine, fluid-pressure mechanism for moving the jack, a fluid-prels' sure" circuit including a pressure generating source, an operator-controlled valve member for establishing communication between mechanism and said circuit, and a pressure selective member associated with the valve member for causing an increase of the pressure'of the fluid in said circuit after the'jack has been moved by said mechanism.

locking valves Hi2, 292 become opened so that 3; In a shoe machine, a chit" shaft; slut-en: tripping mechanism for causing rotation of the shaft,- a movable shoe-supporting jack adapted to locate a shoe in operativeposition in the chine, fluid-pressure mechanism for moving the jack, a fluid pressure" circuit including a pressure generating source, means for connecting said mechanism with said circuit, selective means associated with the connecting means for cans-- ing an increase of the pressure of the fluid in said circuit after the jack has located the shoe in operative position, and fluid-pressure means adapted upon increase of the pressure of the fluid in said circuit to operate the emanate: ping mechanism. U

4. In a shoe machine, a clutch shaft, clutch-f tripping mechanism for causing rotation of the shaft, a movable shoe-supporti'i'ig jack adapted to locate a shoe in operative position in the m schine, fluid-pressure mechanism for moving use jack, a fluid-pressure circuit including a pres; sure generating source, an cperatoi' coritrolied valve member for establishing communication between said mechanism and saidcircuit, a e 1 sure selective member movable with the valve member for causing an increase of the pressure of the fluid in said circuit after the jack been moved to locate the shoe in operative tion, and a fluid-pressure ram adapted upon "1; crease of the pressure of the fluid in said circuit to operate the clutch-tripping mechanism;

5. In a shoe machine, a clutch shaft, clutchtripping mechanism for causing rotation of the shaft, a" movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, fluid-pressure mechanism for moving the jack, a fluid-pressurecircuit including a pr s: sure generating source, an operator-controlled valve member for establishing communication be tween said mechanism and said circuit, a pressure selective member movable with the valve member for causing an increase of the pres sure of the fluid in said circuit after the jack has been moved to locate the shoe in operative position, a fluid-pressure ram connected to said circuit and adapted topper-are the clutch: tripping mechanism, and a spring tending to maintain the ram inoperative, the spring being adapted to yield upon increase of the pressure of the fluid in the circuit to permit the operation of the ram.

6-. In a shoe machine, a movable shoe-support ing jack adapted to locate a shoe in operative position in the machine, fluid-pressure mecha nism for moving the jack, a fluid-pressure circuit including a low-pressure regulator and a high-pressure regulator, means for connecting said mechanism with said circuit, and means associated with the connecting means" for cutting oil the low-pressure regulator from the circuit after the jack has" located the shoe in operative position.

7-. In a shoe machine, a clutch shaft, clutch tripping mechanism for causing rotation of the shaft, a movable shoe-supporting jack adapted to locate a shoe'in operative position in the Inachine, fluid-pressure mechanism for moving the jack,- a fluid-pressure circuit including a lowpressure regulator and a high pressure regulator; an operator-controlled valve member for establishing communication between said mechanism and-said circuit, a pressure selective member inte'gral' with the valve member for cutting err the low-pressure regulator from the circuit after the jack has been moved to mate the'sh'oe iii operative position, and a fluid-pressure ram adapted after cutting off the low-pressure regulator from the circuit to operate the clutch-tripping mechanism.

, 8. In a shoe machine, a clutch shaft, clutchtripping mechanism for causing rotation of the shaft, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, fluid-pressure mechanism for moving the jack, a fluid-pressure circuit including a lowpressure regulator and a high-pressure regulator, an operator-controlled valve member for establishing communication between said mechanism and said circuit, a pressure selective member integral with the valve member forcutting 01f the low-pressure regulator from the circuit after the jack has been moved to locate the shoe in operative position thereby increasing the fluid pressure of the circuit, a fluid-pressure ram connected to said circuit and adapted to operate the clutch-tripping mechanism, and a spring tending to maintain the ram inoperative, the spring being adapted to yield upon increase of the fluid pressure of the circuit to permit the operation of the ram.

9. In a shoe machine, a work abutment, a shoe-supporting jack adapted to elevate and clamp a shoe against the abutment, a source of hydraulic pressure, hydraulic jack-elevating mechanism, a low-pressure hydraulic circuit, an operator-controlled valve member for establishing hydraulic communication between said mechanism and said circuit, and pressure selective means associated with said valve member for causing an increase of the pressure of the fluid in the circuit after the jack has been elevated toclamp the shoe against the abutment.

10. In a shoe machine, a clutch shaft, clutchtripping mechanism for causing rotation of the shaft, a work abutment, a shoe-supporting jack adapted to elevate and clamp a shoe against the abutment, hydraulic jack-elevating mechanism, a low-pressure hydraulic circuit, an operatorcontrolled valve member for establishing hy-' draulic communication between the jack-elevating mechanism and the hydraulic circuit, means associated with said valve member for causing an increase of the pressure of the fluid in the circuit after the jack has been elevated to clamp the shoe against the abutment, and a hydraulically operated mechanism adapted upon increase of the pressure of the fluid in the circuit to operate the clutch-tripping mechanism.

11. In a shoe machine, a clutch shaft, clutchtripping mechanism for causing rotation of the shaft, a work abutment, a shoe-supporting jack adapted to elevate and clamp a shoe against the abutment, .a source of hydraulic pressure, hydraulic jack-elevating mechanism, a low-pressure hydraulic circuit, an operator-controlled valve member for establishing hydraulic communication between the jack-elevating mechanism and the hydraulic circuit, pressure selective means associated with said valve member for causing an increase of the pressure of the fluid in the circuit after the jack has been elevated to clamp the shoe against the abutment, a hydraulically operated mechanism connected to said circuit and adapted to operate the clutch-tripping mechanism, and a spring tending to maintain the last-mentioned hydraul cally operated mechanism inoperative, the spring being adaoted'to yield upon increase of the pressure of the fluid in the circuit to'permit the operation of said hydraulically operated mechanism.

12. In a shoe machine, a work abutment a'. shoe-supporting jack adapted to elevate and clamp a shoe against the abutment, a hydraulic ram for elevating the jack, a hydraulic circuit including a low-pressure regulator and a highpressure regulator, an operator-controlled valve member adapted to establish communication between the hydraulic ram and the hydraulic circuit, and a pressure selective member movable with the valve member and adapted to cut off the low-pressure regulator from the circuit after the elevation of the jack.

13. In a shoe machine, a clutch shaft, clutchtripping mechanism for causing rotation of the shaft, a work abutment, a shoe-supporting jack adapted to elevate and clamp a shoe against the abutment, a hydraulic ram for elevating the jack, a hydraulic circuit including a low-pressure regulator and a high-pressure regulator, an operator-controlled valve member adapted to establish communication between the hydraulic ram and the hydraulic circuit, a pressure selective member movable with the valve member and adapted to cut off the low-pressure regulator from the circuit after the elevation of the jack so as to cause an increase of the pressure of the fluid in the hydraulic circuit, and another hydraulic ram adapted upon increase of the pressure of the fluid in the circuit to operate the clutch-tripping mechanism.

14. In a shoe machine, a clutch shaft, clutchtripping mechanism for causing rotation of the shaft, a work abutment, a shoe-supporting jack adapted to elevate and clamp a shoe against the abutment, a hydraulic ram for elevating the jack, a hydraulic circuit including a low-pressure regulator and a high-pressure regulator, an operator-controlled valve member adapted to establish communication between the hydraulic ram andthe hydraulic circuit, another valve member movable with the first-mentioned valve member and adapted to out 01f the low-pressure regulator from the circuit after the elevation of the jack so as to cause an increase of the pressure of the fluid in the hydraulic circuit, another hydraulic ram connected to said circuit and adapted to operate the clutch-tripping mechanism, and a spring tend ng to maintain the last-mentioned ram inoperative, the spring being adapted to yield upon increase of the fluid pressure of the circuit to permit the operation of said last-mentioned ram.

15. In a shoe machine, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, a power-operated cam shaft, a cam on the cam shaft, fluid pressure jack-operating mechanism, a fluid-pressure circuit including a pressure generating source, means for connecting the jack-operating mechanism with the fluid-pressure circuit, pressure selective means associated with the connecting means for causing an increase of the fluid pres-'- sure of the circuit after the jack has located the shoe in operative position, means for locking the jack-operating mechanism in operative position, and means under the control of said cam for releasing the locking means at a predetermined point in each machine cycle.

16. In a shoe machine, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, apower-operated cam shaft, a cam on the cam shaft, hydraulic jack-operating mechanism, a source of hydraulic pressure, a low-pressure hydraulic circuit, an operatc ec ntrolledj v v member for'hydralll-ifiallyl nn c n t e i c ronerat ne mechamsmtw th: said circuits; a pressure selective; member, integral, I

mechanism in operative position,;.and, 1 means under the control, of said camni r, r l asin t locking means at a predetermined point in each machinecycle.

.:-a s oe machinaa clutchecontrolledicam shaft, clutch-tripping mechanism for causing rotation of the shaft, a cam on the shaft, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, hydraulic jack-operating mechanism, a source of hydraulic pressure, a low-pressure hydraulic circuit, a valve member for establishing communication between the jack-operating mechanism and said circuit, a pressure selective member movable with the valve member for causing an increase of the fluid pressure of said circuit after the jack has been moved to locate the shoe in operative position in the machine, means for hydraulically locking the jack-operating mechanism, hydraulic means for operating the clutch-tripping mechanism upon increase of the fluid pressure of th hydraulic circuit, and means under the control of said cam for releasing the locking means at a predetermined point in each machine cycle.

18. In a shoe machine, a clutch-controlled cam shaft, clutch-tripping mechanism for causin rotation of the shaft, a cam on the shaft, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, a cylinder, a piston movable in the cylinder to move the jack, a hydraulic circuit including a lowpressure regulator and a high-pressure regulator, an operator-controlled valve member for admitting pressure fluid from said circuit to said piston to operate the jack, a pressure selective member integral with the valve member and adapted to cut off the low-pressure regulator from the circuit so as to increase the fluid pressure of the circuit after the jack has been moved to locate the shoe in operative position in the machine, hydraulic means for operating the clutchtripping mechanism upon increase of the fluid pressure of the circuit, a spring-biased valv for severing the hydraulic connection between the cylinder and the circuit to lock the piston and jack in operative position, and means under the control of said cam for opening the last-mentioned valve to release the jack at a predetermined point in each machine cycle.

19. In a shoe machine, a movable shoe-sup- :porting jack adapted to locate a shoe in operative position in the machine, a power-operated cam shaft, a cam on the cam shaft, fluid-pressure jack-elevating mechanism, a source of fluid under pressure, means for connecting the jack-elevating mechanism with the source of fluid under pres sure, means associated with the connecting means for increasing the fluid pressure of the circuit after the jack has located the shoe in operative position, means for locking the jack-elevating mechanism in operative position, and means under the control of the cam for periodically rendering the locking means operative and causing a downward movement of the jack.

20. In a shoe machine, a cam shaft, a clutch on the shaft, clutch-tripping mechanism, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, a hydraulic toresist further}, actuation of the v lve, mea -35'".-

en edw e'thera eta a tive-e r a of? continued ,movement pf the operates-controlled e b r: ains er i e e ie i iw neri s t i qie .l r' su e t-t e p t i iMi d; ctive as av result;of,the increase of the rene ad s p r te 11 ?i1 u h* p p n mechanism.

21. In a shoe machine, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, fluid-pressure :mechanism for moving the jack, a fluidepressure circuit, a conduit between the circuit and the fluidpressure mechanism, an operator-controlled valve in said conduit for establishing communication between said mechanism and said circuit, another valve in said conduit and designed to retard the flow of fluid from the fluid-pressure mechanism.

22. In a shoe machine, a vertically reciprocating shoe-supporting jack adapted to elevate a shoe into operative position in the machine, fluidpressure mechanism for elevating the jack, a supply of fluid under pressure, a conduit between the supply and the elevating mechanism, an operatorcontrolled valve in said conduit for establishing communication between the supply and the elevating mechanism, another valve in said conduit and designed to retard the drainage of pressure fluid from the elevating mechanism.

23. In a shoe machine, a clutch shaft, clutchtripping mechanism for causing rotation of the shaft, a vertically reciprocating shoe-supporting jack adapted to locate a shoe in operative position in the machine, a hydraulically operated ram for elevating the jack, a hydraulic circuit, a conduit between the circuit and the ram, an operator-controlled valve in the circuit for establishing communication between the circuit and the ram, another valve in the conduit designed to retard the return of pressure fluid from the ram, means associated with the first-mentioned valve for increasing the fluid pressure of the hydraulic circuit after the jack has located the shoe in operative position, and fluid-pressure means adapted upon increase of the fluid pressure of the circuit to operate the clutch-tripping mechanism.

24. In a shoe machine, a movable shoe-supporting jack adapted to locate a shoe in operative position in the machine, a power-operated cam shaft, a cam on the cam shaft, fluid-pressure jack-operating mechanism, a fluid-pressure cir cuit, means for connecting the jack-operating mechanism with the fluid-pressure circuit, means associated with the connecting means for increasing the fluid pressure of the circuit after the jack has located the shoe in operative position, valve means for locking the jack-operating mechanism in operative position against movement in opposite directions, and means under the control of said cam for releasing the locking means at a predetermined point in each machine cycle.

and jack in operative position against upward as well as downward movement, and means under V the control of said cam for opening the said" spring-biased valves to release the jack at a predetermined point in each machine cycle. FRANK R. THRESH;

REFERENCES CITED The following references are of record iii the i file of this patent:

FOREIGN PATENTS Country Date Great Britain Sept. 29, 1937 N umber Certificate of Correction Patent No. 2,541,132 February 13, 1951 FRANK R. THRESH It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 15, line 42, after the Word and comma abutment, insert a source of hydraulic pressure,; line 46, before means, lnsert pressure selective;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 5th day of June, A. D. 1951.

THOMAS F. MURPHY,

Assistant Uommz'ssz'aner of Patents. 

